It was a rough Monday morning. I had woken up at the crack of dawn to go train a client, and this was the first thing I heard. I hadn’t even hooked up my coffee IV yet.

I had a choice. I could appease my well-paying client and nod my head in understanding, offering a sympathetic “mmhmmm” every now and then. Or I could educate him. I went with the latter.

Almost everyone has dealt with some sort of weight loss plateau. You feel like you’re doing everything right, and out of nowhere the scale stops moving. What gives?

Generally this is where we play the blame game and decide that our metabolism has to be the culprit. It makes intuitive sense. Metabolism has to be why some people can lose weight while eating terrible foods, and others gain weight by looking at an apple the wrong way.

A quick Google search gives us this definition: “Metabolism is the chemical processes that occur within a living organism in order to maintain life.”

That doesn’t really tell us what we want to know, though. Metabolism can be broken down into various components.

The most basic form is Basal Metabolic Rate, or BMR. This baseline metabolic rate is the amount of calories someone burns each and every day to maintain life.

Just living requires quite a bit more energy than we think. There are thousands upon thousands of chemical reactions taking place in our body at any given second. These have to be fuelled somehow, which is where we get metabolism. Usually this number is in the 1,600-2,000 calorie per day range for an average sized male. And the bigger this individual, the more calories they burn to maintain life.

BMR is important to understand, because someone saying they have a slow metabolism is literally saying they struggle to maintain life. And while that may feel true when you’re fighting a massive hangover, it’s likely not the case. There are very few instances where a truly slow metabolism exists.

Metabolism is more complicated than just BMR though. It’s influenced by a number of other factors. Two factors that have a very large influence are NEAT and TEF.

NEAT, or “non-exercise activity thermogenesis”, is the calories we burn each day by walking, fidgeting, cleaning dishes, etc. This number varies greatly from person to person; some estimates put NEAT as high as 900 calories per person.

TEF, or “thermic effect of feeding”, is the calories we burn by digesting foods. One of the big reasons that high protein diets tend to work well, outside of helping keep you full, is protein has a higher TEF than any other food. When you eat more protein, you’ll burn more calories than if you ate the same amount of carbs or fats.

All of these factors combined usually lead to the average male burning around 2,000-2,500 calories per day.

So where did we get the concept of a slow metabolism?

The idea of having a slow metabolism probably stems from the fact that as we age we lose lean muscle mass, and our metabolic processes tend to slow down. These factors combine to cause a decrease in metabolic rate of about 2-8% per decade, or anywhere from 40 to 160 calories.

Most of us understand that our metabolism slows as we age, but we often grossly overestimate that number – especially when factoring in the favourable impact to metabolism that strength training can provide.

Gender differences and metabolism
One of the biggest things I hear from female clients is how much more difficult it is for them to drop weight because they have a slower metabolism, and this is true. Females have less muscle mass and a slower metabolism than their male counterparts.

The difference isn’t big enough to become that valid of an excuse, though. The difference in BMR between a male and female that are the exact same size is usually right around 3%. Or, for someone who burns 2,000 calories per day, 60 calories per day.

If a slow metabolism isn’t stopping you from losing weight, what is?

Most clients I work with are focused on dropping fat. They’ve probably dieted before, and know how to eat well. Hell, most report that they don’t eat poorly to begin with.

But they don’t understand just how much they’re actually eating. Us humans are notoriously awful at gauging our caloric intake. In our world of widely available, hyper-palatable food, we’re downright terrible at estimating how much we eat.